I connected the reader as per the diagram on the seller's product page. (see attached pic)

I understand that it is using the resistors as a voltage divider to supply 3.3V to the inputs of the SD card. I read on some articles that you need to supply 3.3 V inputs (MOSI, CS, CLK) or you can burn your card. I measured the voltage level going into the card on some of those pins and it is 3.3VThe diagram says to use 3.3k with 1.8k on MOSI and CS, 1k with 2.2k with SCK. I did not have exactly those so I used 1.5k and 3k everywhere which gives me the almost exact 3.3V as mentionned above.

I am using pin 10 for slave select, reflected in my code. I know some people have used a level shifter instead for this in certain articles.

The setup section fails on init, I tried 2 cards on it.I checked my wiring, and I find nothing wrong with it so far. I still have some troubleshooting to do, but want to know if this setup has a shot at working or not.

if (!SD.begin(SD_SS_pin)) { Serial.println("initialization failed!"); return; } Serial.println("initialization done."); // open the file. note that only one file can be open at a time, // so you have to close this one before opening another. myFile = SD.open("test.txt", FILE_WRITE);

Yes it does have a 3.3V regulator, but that is for its operating voltage as far as I understand, but the inputs coming from the MCU are 5V and those, the card does not regulate. This is what I read so far is the issue.

Found one problem, I could not get it to work with my arduino mini. Tried my uno and a 128m card and it worked fine, but a 1gig sd micro card with sd adapter never worked.

Based on the good ladyada article, I need a logic level converter to get it to work properly I think. That or get a better card reader. What do you expect for a 2$ sd card reader module? Resistor dividers are clearly nfot ideal for that setup according to the article.

Adafruit's reader has a logic level converter.

Is looking at it this way good?: as long as you know exactly what you are getting, ebay is fine?

I never buy those cheap ones. What if it stops working when you're saving important data (like temperature of your bathroom )

There are many resistors on the board. I can't see their markings but suspect they each connect to an SPI pin to prevent damage. If you want reliable results, use level shifters. Adafruit sells an sd module for like $15 (I know it's expensive). I use their sd logger shields. Didn't seem to have failed yet. I have dozen of them.